JPS6172617A - Production of crystalline aluminosilicate zeolite - Google Patents

Abstract

PURPOSE:To produce crystalline aluminosilicate zeolite having large crystal particle diameters, by using silica-alumina sol as a silica source and an alumina source to prepare an aqueous mixture as a precursor, and synthesizing zeolite under a conventional condition. CONSTITUTION:Silica-alumina sol is used as a common feed source for silica and alumina to prepare an aquous mixture having the following molar ratio. SiO2/Al2O3=2-170; A/SiO2=0.01-10 (A is basic organic compound or inorganic compound); H2O/SiO2=5-300. The aqueous mixture is reacted at enough temperature for enough time to crystallize aluminosilicate zeolite, to give the desired crystalline aluminosilicate zeolite. Preferably the silica-alumina sol having 4-300nm dispersed particle diameters, and the alumina content has 1-50wt% silica content.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a crystalline aluminosilicate zeolite having a large crystal particle size.

As is well known, crystalline aluminosilicate zeolites (hereinafter simply referred to as zeolites) have useful properties such as molecular sieving, moisture absorption, ion exchange ability, and catalysis, and have long been used as adsorption/separation agents. It is widely used as a desiccant, ion exchange agent, catalyst, etc. However, since synthetic zeolite generally has a particle size of about 1μ at most, it is difficult to use it for the industrial applications mentioned above.
It is customary to mix in a binder such as clay and shape the particles to the desired particle size. However, molding zeolite by mixing a binder has the disadvantage that the molded particles have pores derived from the binder that are different from the pores inherent in the zeolite. If it is almost the same as that of zeolite, it may adversely affect the molecular sieving action of zeolite. In addition, since the binder acts as a diluent for the zeolite, the use of a binder has the disadvantage of reducing the inherent performance of the zeolite.

Therefore, in order to fully utilize the inherent performance of zeolite, it is preferable to produce zeolite with larger crystal particles and use it as it is without adding a binder or the like. Furthermore, since the heat resistance of zeolite generally increases as the crystal grain size increases, it is desirable to increase the crystal grain size in this respect as well.

As a method for producing zeolite with large crystal particles, as shown in Japanese Patent Publication No. 55-36603, silica-alumina with large particle size is prepared in advance by a spray drying method, etc.
There is a known method in which this is then calcined at a high temperature and then treated with an alkaline solution to perform hydrothermal synthesis. In addition, J.

Cryst, Growth, 8, 219 (
(1971), sodium aluminate and sodium silicate were dissolved in triethanolamine aqueous solutions prepared separately, and both solutions were filtered through a 0.2μ microfilter, and then the respective filtrates were mixed while stirring. A method is taught for producing large and type X zeolites consisting of large single crystals by gelation followed by hydrothermal synthesis.

The present invention is a completely different method from the conventional method introduced above, and is intended to produce zeolite with a large crystal particle size. The present invention shows that if an aqueous mixture as a precursor of synthetic zeolite is prepared using the conventional zeolite synthesis conditions, zeolite having a large crystal particle size, specifically, a crystal particle size of at least about 2 μm can be produced. they found out.

The method for producing zeolite with large crystal particles according to the present invention is a method for producing zeolite by reacting an aqueous mixture having the following molar ratio at a temperature sufficient for crystallization of the zeolite for a sufficient period of time. In this case, 8i0. / AltO, w 2 ”” 170 people
/8i0. TS 0.01~10I(,0/810
．． -5 to 300 (A represents a basic inorganic compound or organic compound) When preparing the aqueous mixture gold, a silica-alumina sol is used as a common source of silica and alumina.

In the present invention, silica-alumina sol refers to so-called hydrosil in which colloidal particles of silica-alumina are dispersed in water. Generally, silica-alumina dorosol has a solid content concentration in the range of about 20 to about 30 wt%, and the particle size of the dispersed particles is usually in the range of 3 to 4 ooonm, and the present invention also uses this type of dorosol. Silica-alumina sols can be used. However, particularly in the present invention, it is preferred to use a silica-alumina sol with an alumina content of 1 to 50% by weight of silica. This is because if the alumina concentration is high, the silica-alumina sol itself lacks dispersion stability, and if the concentration is lower than this, it may be necessary to find another alumina source. The silica-alumina sol suitable for use in the present invention can be prepared, for example, by adding a silicic acid solution and a sodium aluminate solution to the silica sol at the same time and stirring while stirring to completely build up the colloidal particles, and then adding It can be easily prepared by removing the soda content with an ion exchange resin and then heating and concentrating it.

Conventionally, basic inorganic compounds such as alkali metal compounds, alkaline earth metal compounds, and ammonia, and basic organic compounds such as amines and amides have been used as bases required for zeolite synthesis, but the method of the present invention also uses them. Any of these can be used.

According to the method of the present invention, a silica-alumina sol, a base and water as described above are used to prepare an aqueous mixture having a molar ratio within Range 1, preferably Range 2 below.

Range 1 Range 2 7 people to 81 1,0,2~170 5~100A/
Sin, 0.01~10 0.05~2H,
O/8i0. 5-300 10-100 (
When preparing an aqueous mixture, the present invention requires that all of the silica necessary for this be provided by silica-alumina sol, and for alumina, it is also necessary to use silica-alumina sol. It is best to cover everything. However, if the alumina content of the silica-alumina sol used is low, an alumina source other than the silica-alumina sol may be used, provided that the amount of alumina is less than 3 Qwt%, preferably less than 2Qwt%, of the amount of alumina required for the aqueous mixture. In such a case, the alumina source can be, for example, the commonly used aluminum salts such as sodium aluminate and aluminum sulfate, aluminum hydroxide, and alumina. can.

After preparation of the aqueous mixture, it is aged preferably at a temperature of 20-70°C for at least 1 hour and then reacted for a sufficient time at a temperature sufficient to crystallize the zeolite, so that the crystal particle size is reduced to 2. Zeolites in the range of ~100μ can be produced. The reaction temperature is 70~Zoo''
C, the reaction time is generally in the range of 5 hours to 7 days. The reaction pressure may be normal pressure or increased pressure, and even when the reaction is performed under increased pressure, the autogenous pressure is sufficient. In addition, when crystallizing zeolite, as usual, inorganic acids such as sulfuric acid, organic acids such as calzenic acid, halides such as sodium, potassium, and norium,
Furthermore, sulfates and the like can also be used in the present invention. These mineralizers can be added directly to the aqueous mixture or can be formed in the aqueous mixture.

The crystallized zeolite is filtered from the reaction medium, washed with water, and generally dried and calcined. The zeolite obtained by the method of the present invention, like conventional synthetic zeolites, contains at least a portion of its cations as hydrogen, hydrogen precursors, and cations selected from Groups 1 and 1 of the periodic table. Or it can be ion exchanged with a cation mixture. Furthermore, since the zeolite obtained by the method of the present invention has a large crystal particle size, it can be used as an adsorption/separation agent, desiccant, ion exchange agent, catalyst, and even catalyst support without using a binder or the like. It is possible.

As described above, according to the method of the present invention, zeolite having a large crystal particle size can be produced, but the reason for this is not necessarily clear at present. However, when using silica sol, silica gel, water glass, etc. as the silica source, and when using sodium aluminate, aluminum sulfate, etc. as the alumina source, it is possible to produce zeolite with a crystal particle size of about 1μ at most. There is no doubt that using silica-alumina sol as both a silica source and an alumina source is extremely important in producing zeolite with a large crystal particle size.

Example 1 381.0 g of sodium hydroxide solution (4a, svt% NaOH) was dissolved in 251.7 g of water, and silica-alumina sol (2,28
wt%N~Or 21.32wt% sho, ,
4.6 sWt Chi people 1,0. )2814.3gt was added to prepare an aqueous mixture having the following composition.

2.6Na,O: AltOs: 7.74SiO,:
106H,0 This aqueous mixture was aged at room temperature for 16 hours, then kept at normal pressure at 95°C for 48 hours to form crystals, and the product was then filtered off, washed with water, and aged at 110°C for 1
It was dried for 6 hours.

The obtained product was analyzed by X-ray diffraction method, and this product was also OH81.
It was confirmed that the zeolite was a Y-type zeolite with a 0,/AttO,O moy ratio of 4.3 and a crystallinity of 106. The crystallinity of Y-type zeolite is determined by calculating the total peak area of (533) and (642) planes (5tl), and calculating the total peak area So It was calculated from the following formula assuming ft crystallinity as 100%.

Crystallinity -1008/S.

Further, a scanning electron micrograph of the zeolite obtained in this example is shown in the drawing (1 scale - 10μ).

As is clear from the drawings, the crystal particle size of this zeolite is in the range of 10 to 20 microns.

Example 2 Using the same starting reactants as in Example 1, an aqueous mixture of the following composition was prepared.

2.4Na,O: Al2O,: 7.748i0.
: 106H20 This aqueous mixture was treated under the same conditions as in Example 1, and the resulting product was analyzed by X-ray diffraction, and it was found that the solubility ratio of S402/Al, O8 was 4.
6. It was a Y-type zeolite with a crystallinity of 109%. In addition, the crystal particle size of this zeolite is
It was confirmed by a microscope that it was 8 to 12μ.

Example 3 Chestnut An aqueous mixture of the following composition was prepared using the starting reactants used in Example 1 and sodium gold iodide.

2.6Na,O: Al2O3: 7.74Sia1:
106H,O: NaI This aqueous mixture was treated under the same conditions as in Example 1, and the resulting product 2 was analyzed by X-ray diffraction, and was found to be a faujasite-type zeolite with a crystallinity of 90%. . Further, the crystal particle size of this zeolite was confirmed to be 8 to 20A using a scanning electron microscope.

Example 4 91.1 g of sodium hydroxide solution (49.5 wt%
NaOH) and 9.1 g of water were mixed, and silica-alumina sol (2.97 w
t%Na, 0.21.92wt%Sin, 4.0
9 wt% Altos) was added to prepare an aqueous mixture having the following composition.

2,6 Na, O: Altos: 9.115ift
: 106H20 This aqueous mixture t- After aging at room temperature for 16 hours, it was kept at normal pressure at 95°C for 96 hours to form crystals, and the obtained product t- was filtered off, washed with water, and heated to 110"C.
It was dried for 16 hours. This product was then analyzed by X-ray diffraction and found to be gmelinite zeolite. Further, the crystal particle size of this zeolite was confirmed to be 6 to 10 μm using a scanning electron microscope.

Example 5 An aqueous mixture having the following composition was prepared using the starting reactants used in Example 4 and sodium aluminate.

2.6 Na, O: Person 120. : 6.08iO
,: 106H,0 This mixture was aged for 16 hours at room temperature and kept at 95°C for 24 hours to form crystals.The obtained product was filtered, washed with water, and dried at 110°C for 16 hours. When this product was analyzed by t-X-ray diffraction method, it was found that the molar ratio of 5IO2/Al2O was 4.2,
It was a YW zeolite with a crystallinity of 107%. Furthermore, it was confirmed by scanning electron microscopy that the crystal particle size of this zeolite was 4 to 8 microns.

Comparative Example 1 Instead of the silica-alumina sol used in Example 4, silica sol (0.04 wt% Na2O, 20.18 wt%
5iQ2. An aqueous mixture of the following composition was prepared using the starting reactants and sodium aluminate used in Example 4, except that 0.03 wt.

2.6 NatO: Al, O8: 6. To O8i: 1
061(,0After aging this mixture for 16 hours at room temperature,
A portion of the sample was filtered and washed with water at 24 hours, 72 hours, and 96 hours while being maintained at 95°C, and each sample was dried at 110''C for 16 hours.

Next, each sample was analyzed by X-ray diffraction method, and all of them were S10. / It was a Y-type zeolite with a molar ratio of Al and O of 4.2 and a crystallinity of 105%. Furthermore, by scanning electron microscopy, the crystal grain size of each sample was 1 μm.
It has been confirmed that the following is true.

[Brief explanation of the drawing]

The drawing is a scanning electron micrograph of the zeolite obtained in Example 1. Manabu Shiga, Commissioner of the Patent Office1. Incident indication 1982 Patent Application No. 193715 2.5 @ Ming name Crystalline aluminosiligou 1 - Zeolite manufacturing method 3,
Relationship with the case of the person making the amendment Patent applicant: 2-6-2 Otemachi, Chiyoda-ku, Tokyo Catalysts and Chemicals Industry Co., Ltd. Representative: Tadashi Ishiguro 4, Agent 5, Date of amendment order 7, Contents of amendment (1) ) “Zeorai 1-
What is the description of "scanning"? "Scanning of Zeolite Crystal Particles" and correction. that's all.

Claims (1)

[Claims] 1. Preparing an aqueous mixture having the following molar ratio and reacting this mixture at a temperature sufficient for a sufficient time to crystallize the aluminosilicate zeolite to produce a crystalline aluminosilicate zeolite. In the method, SiO_2/Al_2O_3 = 2 to 170 A/SiO_2 = 0.01 to 10 H_2O/SiO_2 = 5 to 300 (A represents a basic inorganic compound or an organic compound) When preparing the above aqueous mixture A method for producing a crystalline aluminosilicate zeolite, characterized in that a silica-alumina sol is used as a silica source and an alumina source. 2. The dispersed particle size of the silica-alumina sol is 4 to 3.
2. A method according to claim 1, characterized in that the alumina content is in the range of 1 to 50 wt% of the silica content.